Apparatus and method for the thermochemical treatment of materials



June 3 1924. 1,496,467

C. B. JACOBS APPARATUS AND METHOD FOR THE THERMOCHEMICAL TREATMENTOFMATERIALS Original Filed June 28, 1919 3 Sheets- Sheet 1 A INVENTORAPPARATUS AND METHOD FOR THETHERMOCHEMICAL TREATMENT OF MATERIALS 3Sheets-Sheet 3 Ofiginal Filed June 28 1919 C. 5. Jacos Jame 3 9 192%3,496,437

C. B. JACOS APPARATUS AND METHOD FOR THE THERMOCHEMICAL TREATMENT OFMATERIALS Original Filed June 28, 1919 3 Sheetg-Sheet 3 WW Z2 2MINVENTOR ATTORNEY Patented June 3, 1924.

entree stares 1,496,467 PATENT 'oFFIcE.

CHARLES E. JACOBS, OF WILMINGTON, DELAWARE; ASSIGNOR TO E. I. DU FONT DENEMOURS & COMPANY, OF WARE.

WILMINGTON, DELAWARE, A CORPORATION OF DELA- APPARATUS AND METHOD FORTHE THERMOCHEMICAL TREATMENT OF MATERIALS.

Application filed To all 10h am it may concern.

Be it known that I, CHARLES B. Jaooes, a citizen of the United States,and a resident of Wilmington, in the county of New Castle and State ofDelaware, have invented a certain new and useful Apparatus and Methodfor the Thermochemical Treatment of Materials, of which the following isa spec1- fication.

This invention relates to apparatus for use in the performance ofthermochemical operations, and has for an object the provision ofapparatus by the use of which such operations can be carried out in anefficient, economical and commercially practicable manner. It alsorelates to a method of performing certain thermochemical operations,preferably while making use of such apparatus, and has for anotherobject the providing of such a method.

To the ends set forth and also to improve generally upon apparatus andmethods of the character indicated, my invention consists in thefollowing matters hereinafter described and claimed.

In general, in chemical processes involving thermochemical reactions, itis desirable to carry out the operations in a continuous manner. In manyinstances, however, the nature of the materials used and the conditionsnecessary for successfully carrying out the reactions involved, do notlend themselves to the conditions necessary for continuous operation. Itis in the treatment of such materials that apparatus and methods,

involving the present invention find their most direct application.

Without restricting my invention thereto, I describe it by reference tothe apparatus illustrated in the accompanying drawings, with referenceto the production of alkalimetal cyanides. In order to more plainlybring out the advantages of apparatus and of methods embodying myinvention, I shall first briefly discuss the production of alkalimetalcyanides and the difficulties to be encountered and overcome Inpractically all of the processes extant for the formation ofalkali-metal cyanides, in which free or elemental nitrogen in a purestate, or free or elemental nitrogen in nitrogen-bearing gases, iscaused to combine directly with compounds of the alkali metals andcarbon to form alkali-metal cyanides,

June 28, 1919, Serial No. 307,456. Renewed November 12, 1923.

the chemical reaction involved is expressed empirically by the followingequation:

Alkali-metal cyanides are formed according to the above equation whenintimate mixtures of an alkali-metal carbonate and carbon are subjectedto the action of free or elemental nitrogen at temperatures ranging frombelow 900 C. to above 1000 C., and morereadily when the mixtures ofalkalimetal carbonate and carbon treated, contain certain catalyzingsubstances which aid in the fixation of the nitrogen as alkali-metalcyanides.

In the formation of alkali-metal cyanides, irrespective of the exactcomposition of the charge or of the temperature required to bring aboutthe reaction, it is desirable to carry out the operation in as nearly acontinuous manner as practicable and with this object in view, manyefforts have been made to design and construct furnaces for thecontinuous production of alkali-metal cyanides. But substantially all ofthese efforts have failed to produce a furnace which gave satisfactoryresults under the conditions necessary for operation on a commercialbasis.

The more important conditions favorable to, and the precautionsnecessary for, the eflicient production of alkali-metal cyanides fromfree or elemental nitrogen, carbon, and compounds of the alkali-metalsmay be stated as follows:

Intimate contact is required between more than the theoretical amount ofnitrogen and the other elements of the reacting mass, so constitutedphysically that a large surface of the other reactive elements isexposed to contact with the nitrogen. This condition is usually met bymaintaining thecharge in a porous condition in order that the nitrogenshall not only have free access to all parts of the reactive mass andbecome fixed but also in order that the excess of nitrogen may sweep outand expel the carbon monoxide given off by the reaction and thus effecta high concentration of the nitrogen in contact with the other activeelements throughout all parts of the charge.

The charge at the temperature required for the cyanide reaction is in amore or less plastic condition and any movement or agitation such aswould be caused by pressure necessary for the movement of the chargethrough a stationary retort or furnace or the agitation caused byrotating the retort or furnace tends to compact the charge, destroys itsporosity and causes the nitrogen to form channels and flow along thesepaths of least resistance with consequent failure to come into intimatecontact with all parts of the reacting mass.

The nitrogen supp y should preferably be preheated to the temperaturerequired for the reaction before being admitted to the charge, in ordernot to check or slow up the reaction by cooling the contact points ofthe nitrogen and the other elements of the re-' acting mass below thetemperatures at which the reaction takes In operating with producer gasas .the source of nitrogen, certain additional precautions arenecessary. Carbon dioxide destroys cyanide rapidly even at hightemperatures, and the producer gas used must contain the minimumquantity of carbon dioxide. The cyanide charge cannot be allowed to cooloff in producer gas, since the equilibrium while giving almost pure COabove 900 (3., lower temperatures yields a mixture which is largely CONow, the above conditions are most easily maintained in operating whatis technically known as a batch process, e., a process in which thecharge is placed in a retort or furnace and kept stationary andundisturbed until the reaction is complete, cooled, removed and theoperations repeated). For by this method of procedure the charge can bemaintained in a porous condition and an intimate and uniform contact ofnitrogen maintained; the nitrogen supply can be readily preheated to thereacting temperature before it is introduced into the charge; and, ifproducer gas is the source of nitrogen, the charge may be cooled in theabsence of producer gas by simply shutting off the supply during thecooling period.

But,- in the batch process as ordinarily carried out a long period isrequired to cool the finished charges, which entails a multiplicity offurnaces or retorts to insure sufficient plant capacity, and alsoentails a verylarge. expenditure of fuel in order to reheat the cooledfurnaces or retorts to the reacting temperatures. Hence it is desirableto operate the cyanide process in as nearly a continuous manner aspracticable.

Unfortunately, however, the character of the charge and the temperaturerequired for the reaction are not favorable to continuous operations inwhich any movement of the charge takes place. In the continuous types ofshaft furnaces or retorts', vertical or inclined, in which the charge isfed in place most energetically.-

at the top and discharged at the bottom, the pressure necessary for themovement of the charge tends'to compact it with the attendantdisadvantages pointed out above, unless the charge contains such 'asmall proportion of alkali-metal compounds as to make the yield ofcyanide obtained commercially unprofitable. In the rotary types ofcontinuous furnaces-the agitation ofthe charge by rotation has the samedisadvantageous effects.

A further disadvantage type of furnace for cyanide production is thefact that it is difiicult to use producer gas as the source of nitrogen,since the carbon monoxide in the producer gas coming in contact with thecooled parts of the charge as it is fed towards the outlet of thefurnace is converted into carbon dioxide to such an extent as to destroya large part of the cyanide already formed. Unless the furnace isdivided into heat zones and the producer gas only allowed to come intocontact with the charge in the zone in which the temperature is above900 C. pure nitrogen must be used for the reaction. Now the apparatusand method of the present invention provide for the retention, in theproduction of alkali-metal cyanides, of the desirable conditions of thebatch method, and permit of substantially the same output and fuelconsumption as if the charges were fed continuously through the furnaceor retort.

Briefly stated, the method involving my invention preferably includesenclosing the charge in a thin iron envelope, or secondary retort,perforated at the bottom, which re tort is slipped inside a retortproper which latter remains permanently in a furnace heated to thereacting temperature. The nitrogen is delivered to the charge through aperforated bottom in the envelope. after passing down through theannular chamber formed by the clearance between the inside walls of thepermanent retort and the removable envelope. The products of thereaction are expelled from the charge through an opening in the top oftheenvelope. As to the apparatus e In the accompanying drawings Figure 1is a horizontal section, substantially on line B-B of Figure 2, of afurnace having a plurality ofretorts incorporated therein in accordancewith my invention;

Figure 2 is a vg'rtical section taken substantially on the line A-A ofFigure 1;

Figure 3 is a vertical. diametrical section of an outer retort member:

Figure 4 is a vertical, diametr'ical section of an inner envelopemember;

Figure 5 is a vertical, diametrical section of an inner envelope memberand a retort member assembled;

Figure 6 is a vertical, diametrical section, substantially at rightangles to that of Fig.

of the continuous 5. of a retort member and an inner envelope memberassembled. together with the clamp for holding the two members in fluidtight relation, and

Figure 7 is a top plan view of the asselpbled apparatus.

(In Figures 3 to 6 the retort and envelope are broken out to econoinizespace, while indicating .that the parts are of considerable length ascompared to their diameters.)

Referring now to the drawings A retort member 1, of any suitable size,and constructed desirably of such metal as will resist oxidation by thefurnace gases, or, say, of wrought iron protected by a fire clay jacket,is adapted to be received, pref erably permanently, in the furnace F.head 2 (desirably of cast steel) is carried at the upper end of theretort and presents opposite passages 3 and 4, the passage 3 serving asan inlet and the passage 4 serving as an outlet. As shown, the passage 4opens through the upper surface of the head, for connection with acooperating pascage 5 provided by the head of the inner envelope member,now to be described.

The envelope, or secondary retort, 6 is preferably of thin wrought iron.It is the immediate receptacle for the batch and is designed to beslipped inside the primary retort 1. This envelope is designed to befilled with the batch, introduced into the retort 1, and, at theconclusion of the treatment, removed, together with the contained batch.It will be seen that the apparatus thus provides for the treatment ofthe charges in such a way as to retain the advantages of the batchmethod, while, at the same time, the advantages of continuousfeedinglarge output and small fuel consumption-are obtained. For, anenvelope with i a new batch can be introduced to the retort 1immediately upon the withdrawal of an envelope containing a finishedbatch. Also, the retort proper 1 is kept constantly at operatingtemperature, thus avoiding the deterioration due to alternate expansionand contraction to which it would be subjected if removed from thefurnace to cool, with its contents, to room temperature. Also, theexpenditure of the heat necessary to raise the heavy retort from roomtemperature to reacting temperature is now avoided and confined to theheatnecessary to raise the light sheet iron envelope 6 to operatingtemperatures.-

The envelope 6 is of somewhat less diameter than the retort 1, therebyto provide an annular passage, or chamber, 7 and, as shown, is providedwith perforations 8, in its bottom 6 and with series of perforations 8extending any desired distance above the bottom. As shown the bottom 6is detachably connected with the side wall of the envelope, by the bolts6*. A head or top A when the envelope is 9, preferably of cast steel,is' carried at the upper end of the envelope 6 and is horizontallyextended to be carried bythe head 2 of the retort.1, thereby to supp rtand suspend the envelope 6 within the retort 1. The head 9 presents achamber 10 in communication with the envelope 6 proper. The beforereferred to passage 5 connects the chamber 10 and the outlet passage 4in the head 2. As shown, the inlet passage annular passage 7. It will benoted that the chamber 10 is of restricted cross-sectional dnnensions,compared to the envelope 6 proper, thus the chamber serves to protectthe entrance to passage 5 from clogging being filled from the bottom.

With this arrangement, in operation, nitrogen is introduced through thepassage 3 and follows the path indicated by the arrows (Figs. 5 and 6).The excess nitrogen and the carbon monoxide pass off through the passage4, and desirably the passage 4 is connected to a gas main leading to agas holder, since in commercial operation the escaping gas is valuablefor fuel on account of the carbon monoxide it contains. Desirably thisescaping gas may be used in heating' the furnaces.

In order that the envelope 6 may be closed from air leaks into thecharge, when the envelope and the charge are removed from the furnace, avalve 11 is provided in the passage 4, of any suitable form. As hereshown, it is merely of the rotary plug type.

It will be seen that, with the parts assembled as described, thenitrogen in its passage down from the top of the heated annular chamber7 formed between the inside walls of the retort and the envelopecontaining the charge, becomes preheated to the reacting temperature bythe time it reaches the entrance to the charge in the bottom of theenvelope, thus aiding in supplying heat to the charge from the heattransmitted throughout the charge by the hot nitrogen, the charge beingheated internally and externally instead ofonly externally as in theordinary batch method. Also, the reaction will not be checked by theintroduction of cold nitrogen to the hot charge as is the case to acertain extent in the ordinary batch method of operation.

A chamber element 12, conveniently in the character of a tube closed atthe lower end, suspended from the head 9, and lying in the passage 13,permits the insertion of the thermocouple of a pyrometer. A

The detailed construction of the apparatus may be of any convenient ordesired character. In the illustrated s'tructurez-The head 2 isconnected to a flange 14, unitary with the retort 1, by stud bolts 15.In a similar way the head 9 is connected by 3 in the head 2 communicateswith the if desired).

stud bolts 16 to a flange 17 unitary with the envelope 6, such flange 17having a passage 5' to register with, and form an extension of, thepassage 5. The head 9 comprises a separate portion 18, bolted to thebody of the head by bolts 19, and exteriorly threaded 1 to carry acollar 20. This collar presents upstanding ears 21, 21,- having holes22, 22, provided for receiving a bar for lifting the envelope from theretort member 1, say by means of a travelling crane (not shown). Also,the collar 20 presents a peripheral groove 23. Trunnions 24, 24, areslidably mounted in the groove 23 and serve as a mounting for a lockingmember, or clamp, designated generally as 25 (Fig. 7).

This member comprises sides 26, 26, mounted on the trunnions andcarrying, pivoted between their down-turned ends, latch members 27, 27.These latches are adapted to catch beneath the shoulder 28 of the head2. The latches and the upper surface of the head 9 are cooperativelybevelled as indicated at 9 and 27, 27. The collar 20 is split and may betightened upon the threads of the member 18, as by bolts 29.

With the above described arrangement, after the envelope 6 has beenplaced in the retort 1, the latches 27, 27, are brought beneath theshoulder 28, and the collar 20 screwed upward on the member 18, say by ahandle bar inserted in the holes 22, 22. This forces the heads 2 and 9into gas tight relation (suitable packing 30 may be used The desiredrelation obtained, the collar 20 may be clamped in position by bolts 29to lock the parts in position. Upon moving the collar 20 downward, thebevels 9, 9, and 27 27 cooperate to throw the latches 27, 27 free of theshoulder 28.

Desirably, the head 9 may be provided with passages 31 and 32 forcleaning, or other desired purpose, and closed by plugs 33 and 34, whennot in use.

It will be seen that I have provided an apparatus in which charges maybe treated with the advantages of the batch method, and which providesfor a speed substantially equal to, and a fuel consumption substantiallyno greater than, thoseobtained by a continuous process, without theattendant disadvantages of a continuous process.

The retort, envelope, etc., may be of any suitable dimensions, having inview a sufficient length of the retort 1, envelo e 6 and the chamber 7to furnish the desire amount of preheating of the nitrogen, and soforth.

In carrying out the processes for the production of sodium cyanide inthe above arrangement of apparatus. the method pursued in practice isdesirably as follows: The permanent retorts 1, placed in the furnace F(Figures 1 and 2), are heated to between 950 C. and 1000 C. and theinner envelopes 6 each previously filled with a charge, consisting of,for example: of sodium carbonate 40% of carbon 15% of oxide of iron ofsodium chloride are placed inside the permanent retorts 1, and the headsproperly clamped together as shown in Figures 6 and 7. When a charge hasreached the proper temperature, nitrogen, either pure or in the form ofproducer gas, is introduced through the inlet 3, preferably under apressure of about two atmospheres absolute. The nitrogen passing downthrough the annular chamber 7 as indicated by the arrows, enters thecharge through the perforations 8 and 8 at the bottom of the envelope ata temperature equal to, or slightly greater than, the temperature of thecharge, where it reacts with the elements of the charge, forming sodiumcyanide. The carbon monoxide given off in the reaction, and the excessof nitrogen, pass on up through the charge, the excess of nitro nsweeping the CO with it and expelling it through the outlet of the innerenvelope at 5, valve 11 being open.

When the reaction is complete the supply of nitrogen is shut off, theoutlet valve 11 closed, and the clamp, 25, loosened and the innerenvelope 6 and its contents lifted out of the retort proper 1. Then,another envelope, immediately and without loss of heat from the retort1, and containing a fresh charge, is put in place by means of atravelling crane or overhead hoist, not shown in the drawing, and theoperation repeated. The hot envelope 6 containing the finished charge isdropped into a cooling can not shown, but, struction to the retort 1,except that it is made of thin sheet iron, and water is flowed over itto hasten the cooling of the charge. The envelope with its cooled chargeis removed to the extraction plant and the charge extracted for theproduction of cyanide or hydrolyzed for the production of ammonia as thecase may be.

It will be understood that I may depart widely from the exactarrangement of the apparatus and the details of manipulation withoutdeparting from the spirit of the invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In an apparatus for the thermochemical treatment of materials, incombination,

say, of similar conan outer retort member adapted to be 2. In anapparatus for the thermochemical treatment of materials, in combination,an outer retort member adapted .to be mounted in permanent relation to aheating means, and an inner envelope member removably receivable in saidretort member, there being provided a passage for the introduction offluids t0,-and a passage for the escape of fluids from, said envelopemember, said escape passage being located and arranged for theconducting away. and isolation, from the envelope member of fluidsissuing from said envelope member.

3. In an apparatus for the thermochemical treatment of materials. incombination, an outer retort. member adapted to be mounted in permanentrelation .to a heating means, an inner-envelope member removablyreceivable in said retort member, there being passage means for the flowof fluid through said envelope member, and means independent of saidouter retort member for preventing such flow on occasion whereby saidenvelope member may be cooled while removed from said retort memberwithout the flow of fluid therethrough.

4. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member adapted to be mounted in permanentrelation to a heating means, an inner envelope member removablyreceivable in said retort member, there being passages provided for theintroduction of fluids to, and escape of fluids from, said envelopemember, and a valve in one of said passages to close said passage andprevent entrance of fluids to said envelope through such passages onoccasion.

5. In an apparatus for the thermochemical treatment. of materials, incombination. an outer retort member adapted to be mounted in permanentrelation to a heating means,

an inner-envelope member removablv reeeivable in said retort member,there being passage means for the flow of fluid through said envelopemember with such means including provisions for the conducting away, andisolation, from the envelope member of fluids issuing from the envelopemember, and means independent of said outer retort member for preventingsuch flow on 00-- casion, whereby said envelope member may be cooledwhile removed from said retort member without the flow of fluid therethrough.

6. In an apparatus for the thermochemical treatment of materials, incombination, an

outer retort member adapted to be mounted in permanent relation to aheating means, and an inner envelope member removably receivable in saidretort member, said members being adapted for vertical arrangement,there being provided a passage for the introduction of fluids into saidenvelope member adjacent to the bottom thereof, and a passage for theescape of fluids from such member adjacent to the top thereof, saidescape passage being located and arranged for the conducting away, andisolation, from the envelope member of fluids issuing from said envelopemember. v

7. In-an apparatus for the thermochemical treatment of materials, incombination, an outer retort member adapted to be mounted in permanentrelation to a heating means, an inner envelope member removablyreeeivable in said retort member, there being passages provided for theintroduction of fluids to, and escape of fluids from, said envelopemember, and means in'controlling relatlon to one of said passages forclosing the same thereby to prevent entrance of fluids to saidenvelopethrough such passages on occaslon.

8. In an apparatus .for the thermochemical treatment of materials, incombination, an outer retort member-and an inner envelope memberreceived in. said retort member, said envelope member being smaller thansaid retort member, thereby to provide a fluid chamber between saidmembers, therebeing a fluid inlet passage to said chamer, a fluid outletpassage from said envelope member, anda fluid passage between said twomembers, said various passages being relatively located to rovide forthe passage of fluid into said 0 amber, through a charge contained insaid envelope, and out of said envelope.

9. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member and an inner envelope memberreceived in said retort member, said envelope member being smaller thansaid retort member, thereby to provide a fluid chamber between saidmembers, there being a fluid inlet passage to said chamber adjacent toone end thereof, a fluid outlet passage from said envelope member adjacent to the end thereof in proximity to the said mentioned end of saidchamber. and a fluid passage between the ends of-said chamber and saidenvelope member remote from said first mentioned end of said chamber;whereby fluid introduced through said inlet passage shall pass alongsaid chamber and against the wall of said envelope member, into andalong said envelope member, and from said envelope member.

10. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member and an inner envelope member, bothtubular in character, the envelope member being of less crossdimensionsthan said retort member and so adapted to be received therein as topresent a chamber between the walls of said members, there being a fluidinlet passage to said chamber, a fluid outlet passage from said envelopeand a passage adjacent the end of said envelope remote from said outletpassage and placing said chamber and the interior of said envelope incommunication.

11. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member, an inner retort member, bothtubular in character with the envelope member having a smallercrossdimension than said retort member and adapting it to fit within theretort member,

and means for supporting said envelope member within said retort memberwith the lower end of said envelope member spaced from the adjacent endof said retort, the said end of said envelope member being provided withperforations connecting said chamber and the interior of said envelope,and there being a fluid inlet passage to said chamber and an outletpassage from said envelope. 1

.12. In an apparatus for the thermochemical treatment of materials, incombination, a pair of members the one to be received within the other,to be suspended therein and fastened thereto, and means for suspendingand fastening the received member,-

such means comprising structure upon said receiving member presenting arest surface, a flange upon the received member and located to rest uponsaid rest surface, and means for forcing together and connecting saidrest-surface structure and flange.

13. In an apparatus for the thermochemical treatment of materials, incombination, a pair of members the one to be received within the other,to be suspended therein and'to be fastened thereto, and means for sosuspending and fastening said received member, such means comprising ahead upon the receiving member and presenting a rest-- surface, a flangeupon the received member and locatedto rest upon said rest-surface, ahead received upon said flange, and means for forcing saidheads towardeach other and into contact with said flange.

,14. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member adapted to be mounted in permanentrelation to a heating means, and an inner envelope member removablyreceivable in said retort member,

there being passage means for the flow of fluid through said envelopemember, and said envelope member being provided with an individualclosing top, independent of said outer retort member, whereby saidenvelope member may be removed from said retort member without theopening of said envelope member.

15. In an apparatus for the thermochemi-- cal treatment of materials, incombination, an outer retort member adapted to be mounted in permanentrelation to a heating means, an inner envelope member removablyreceivable in said retort member and havrestricted rec ss meme? ing anopenin and a removable closure therefor, space from the hereafter namedtop longitudinally of said envelope member, there being passage meansfor the flow of fluid relative to said envelope member and said envelopemember being provided with a top having a recess of a cross section-ma-teria-lly less than that of the envelope member proper, and saidassa e means opening into said recess Where y s'aid protects saidpassage during filling 0 said envelope through said opening.-

16. In an apparatus for the thermochemical treatment of materials, incombination, an outer retort member adapted to be mounted in permanentrelation to a heating means, an inner envelope member removablyreceivable in said retort member and having a removable bottom, therebein passage means for the flow of fluid relative to said envelopemember, and said envelope member being provided with a top having arecess of a cross section materially less than that of the envelopemember proper, and said passage means opening into said recess wherebysaid restricted recess protects said passage from the bottom.

17. In an apparatus for the thermochemical treatment of materials, incombination, a pair of members each presenting a head, one of said headspresenting a latch-receiving means and the other alocking-membersupporting means, and means for locking said headstogether, thereby to connect said members, such means comprising alocking member carried by said supporting means and having a latch.

18. In an apparatus for the thermochemical treatment of materials, incombination, a pair of members each presenting a head, oneof said headspresenting a latch-receiving means and the other alocking-membersupporting means, and means for locking said headstogether, thereby to connect said members, such means comprising alocking member carried by said supporting means and having a latch, andprovision for clamping said latch to said latch-receiving means whensaid locking member is moved in one direction relatively to saidsupporting means and for automatically freeing said latch when saidlocking member is moved in another direction relatively to saidsupportingmeans.

19. In an apparatus for the thermochemical treatment of materials, incombination,

during filling of said envelope an inner member and an outer member,each having a head, one of said members also having a flange to liebetween said heads, each said head and said flange presenting each apassage section, said heads and flange and said passage sections beingso 10- cated as toprovide a continuous passage, the we meats? passagesection of one head communicating with the interior of that head, thepassage section of the other head communicating with the exterior ofthat head, and the passage section of said flange connecting the passagesections of the heads.

20. The method of thermochemically treating a batch of material whichcomprises making use of an inner-and-outerreceptacle apparatus with theouter receptacle fixed in a heating means, introducing the innerreceptacle into the outer receptacle, thermochemically treating thebatch while contained in the inner receptacle to bring about chemicalreaction in the batch, removing the inner receptacle while hot, togetherwith the batch, and cooling the batch while unassociated with the outerreceptacle.

21. The method of thermochemically treating a batch of material whichcomprises making use of an inner-and-outer-receptacle apparatus with theouter receptacle fixed in a heating means, introducing the innerreceptacle into the outer receptacle, thermochemically treating thebatch while contained in the inner receptacle to bring about chemicalreaction in the batch, removing the inner receptacle while hot, togetherwith the batch and cooling the batch without access of fluid whileunassociated with the outer receptacle.

22. The method of treating batches of material which comprises makinguse of a plurality of inner receptacles and an outer receptacle, withthe outer receptacle fixed in a heating means, introducing an innerreceptacle into the outer receptacle, treating a first batch whilecontained in the inner receptacle, removing such inner receptacle whilehot, together with the batch, without substantial cooling of the outerreceptacle, and introducing a second batch contained in a second innerreceptacle, into the said outer receptacle while such receptacle retainsthe heat acquired in the treatment of the first batch. i

23. The method of thermochemically treating a batch of material whichcomprises making use of an inner-and-outer-receptacle apparatus with theouter receptaclefixed in a heating means, introducing the innerreceptacle into the outer receptacle, treating the batch by heating andaddition of reactive material while contained in the inner receptacle tobring about chemical reaction in the batch, removing the innerreceptacle while hot, together-with the batch, and cooling the batchWhile unassociated With the outer receptacle.

24. The method of thermochemically treating a batch of material whichcom-.

prises making use of an inner-and-outer receptacle apparatus with theouter receptacle fixed in a heating means, introducing the innerreceptacle into the outer receptacle, treating the hatch by heating andthe addition of reactive material while con tained in the innerreceptacle to bring about chemical reaction in the batch, removing theinner receptacle while hot, together with the batch, and cooling thebatch without access of fluid while unassociated with the outerreceptacle.

25. The method of thermochemically treating batches of material whichcomprises making use of a plurality of inner receptacles and an outerreceptacle, with the outer receptacle fixed in a heating means,introducing an inner receptacle into the outer receptacle, treating afirst batch by heating and addition of reactive material while containedin the inner receptacle to bring about chemical reaction in the batch,removing such inner receptacle while hot, together with the batch,without substantial cooling of the outer receptacle, and introducing asecond batch, contained in an inner receptacle, into the outerreceptacle while such receptacle retains the heat acquired in thetreatment of the first batch.

26. The method of thermochemically treating batches; of material whichcomprises making use of a plurality of inner receptacles and an outerreceptacle, with the outer receptacle fixed in a heating means,introducing an inner receptacle into the outer receptacle.thermochemically treating a hatch while contained in the innerreceptacle, to bring about chemical reaction 1n the batch, removing suchinner receptacle while hot, together with the batch, without substantialcooling of the outer receptacle, and introducing a second batch,contained in an inner receptacle, into the outer receptacle while suchreceptacle retains the heat acquired in the treatment of the firstbatch.

27. The method of producing alkali metal cyanides which consists inmaking use of an inner-and-outer-receptacle apparatus with the outerreceptacle fixed in aheating means, placing a batch of a suitablemixture of alkali metal compound and carbon in the inner receptacle,introducing such receptacle into the outer receptacle, subjecting suchreceptacle to heat and passing nitrogen into the batch, removing theinner receptacle while hot, together with the batch. and cooling thebatch while unassociated with the outer receptacle.

In testimony whereof I afiix my signature.

CHARLES B. JACOBS.

